Basket catheter with deflectable spine

ABSTRACT

A catheter adapted for mapping and/or ablation in the atria has a basket-shaped electrode array with two or more location sensors with a deflectable expander. The catheter has comprises a catheter body, a basket electrode assembly at a distal end of the catheter body, and a control handle at a proximal end of the catheter body. The basket electrode assembly has a plurality of electrode-carrying spines and an expander that is adapted for longitudinal movement relative to the catheter body for expanding and collapsing the assembly via a proximal end portion extending past the control handle that can be pushed or pulled by a user. The expander is also adapted for deflection in responsive to an actuator on the control handle that allows a user to control at least one puller wire extending through the catheter body and the expander.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of and claims priority to and thebenefit of U.S. patent application Ser. No. 14/028,435, filed Sep. 16,2013, issued as U.S. Pat. No. 9,204,929, the entire content of which isincorporated herein by reference.

FIELD OF INVENTION

This invention relates to electrophysiologic (EP) catheters, inparticular, EP catheters for mapping and/or ablation in the heart.

BACKGROUND

Electrophysiology catheters are commonly-used for mapping electricalactivity in the heart. Various electrode designs are known for differentpurposes. In particular, catheters having basket-shaped electrode arraysare known and described, for example, in U.S. Pat. Nos. 5,772,590,6,748,255 and 6,973,340, the entire disclosures of both of which areincorporated herein by reference.

Basket catheters typically have an elongated catheter body and abasket-shaped electrode assembly mounted at the distal end of thecatheter body. The basket assembly has proximal and distal ends andcomprises a plurality of spines connected at their proximal and distalends. Each spine comprises at least one electrode. The basket assemblyhas an expanded arrangement wherein the spines bow radially outwardlyand a collapsed arrangement wherein the spines are arranged generallyalong the axis of the catheter body. The catheter may further comprise adistal location sensor mounted at or near the distal end of thebasket-shaped electrode assembly and a proximal location sensor mountedat or near the proximal end of the basket-shaped electrode assembly. Inuse, the coordinates of the distal location sensor relative to those ofthe proximal sensor can be determined and taken together with knowninformation pertaining to the curvature of the spines of thebasket-shaped mapping assembly to find the positions of the at least oneelectrode of each spine.

It is desirable that a basket assembly be capable of detecting in asingle beat most or all of the electrical function of the left or rightatrium. However, because the atria of an individual patient may vary insize and shape, it is desirable that the basket assembly be sufficientlyversatile and steerable to conform to the particular atrium.Conventional basket catheters have an intermediate deflectable sectionthat is proximal of the basket assembly, but the basket assembly itselfis typically without steerability or deflectability. As such, the basketassembly often lacks sufficient maneuverability and stability to provideuseful contract with enough atrial tissue at any in any single instance.Accordingly it is desirable that a catheter have a basket assembly withimproved maneuverability for better tissue contact, especially in acavernous region of the heart, including an atrium.

SUMMARY OF THE INVENTION

The catheter of the present invention provides the EP physician with aunique tool capable of detecting in a single beat all electricalfunctions of the left or right atrium. The catheter advantageously has amulti-electrode assembly with a steerable elongated expander, whereinthe expander is sufficiently sturdy to support the assembly so as tomaintain all the electrodes adjustably disseminated around the expanderfor enabling contact with surrounding atrial tissue. Puller wires forsteering the expander are anchored distal of the electrode assembly soas to provide improved control and placement of the assembly via thecontrol handle. The improved expander also supports the assembly suchthat the electrodes in the distal portion of the assembly can remain incontact with atrial tissue regardless of the contractions and relaxationcycles of the atria, thus providing physicians with more constantmonitoring and accurate readings on electrical readings and recordingsof the heart. With the multitude of electrodes carried on the assembly,the catheter provides the physician instant and simultaneous view of allelectrical functions within an atrial cavity at a much higher percentageof contact with atrial tissue.

The present invention is directed to a catheter having a basket-shapedelectrode array with two or more location sensors with a deflectableexpander to provide improved mapping and ablation capabilities. In oneembodiment, the catheter comprises a catheter body, a basket electrodeassembly at a distal end of the catheter body, and a control handle at aproximal end of the catheter body. The basket electrode assembly has aplurality of electrode-carrying spines and an expander that is adaptedfor longitudinal movement relative to the catheter body for expandingand collapsing the assembly via a proximal end portion extending pastthe control handle that can be pushed or pulled by a user. The expanderis also adapted for deflection in responsive to an actuator on thecontrol handle that allows a user to control at least one puller wireextending through the catheter body and the expander. The catheter mayprovide a single puller wire for uni-directional deflection of theexpander or two puller wires for bi-directional deflection. Whereas thedegree of curvature of the spines changes similarly (or “symmetrically”)between all the spines when the expander is moved longitudinallyrelative to the catheter body, the degree of curvature of the spineschanges differently (or “asymmetrically”) between the spines when theexpander is deflected. When the expander is moved longitudinally, theassembly as a whole expands or collapses so that the curvature of eachspine is affected similarly by the movement. However, when the expanderis deflected, each spine and its curvature are affected differently bythe deflection, with the curvature in selected spines generallyincreasing and the curvature in opposite spines generally decreasing.The catheter is therefore particularly adapted for mapping and /orablating in a cavernous region of the heart, including the atria.

In one embodiment, the catheter has a proximal junction at the distalend of the catheter body between the catheter body and the expander,wherein the proximal junction includes a tubing whose proximal end ismounted over the distal end of the catheter body, a ring inside thedistal end of the tubing, and a tunnel member is positioned in thethrough-hole, wherein the tunnel member has a lumen through which theexpander extends and is afforded longitudinal movement.

In one embodiment, the catheter has a distal junction at the distal endof the expander, wherein the distal junction includes an outer tubing, aring inside the outer tubing and a puller wire anchor member.

In one embodiment, the spines are mounted in about 360 radial degreesaround the expander. In another embodiment, the spines are mounted inabout 180 radial degrees around the expander.

In one embodiment, at least one spine carries at least one ringelectrode. In another embodiment, the expander carries at least one ringelectrode distal of the distal end of the catheter body.

In one embodiment, the expander has a guidewire lumen.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention will bebetter understood by reference to the following detailed descriptionwhen considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a top plan view of a catheter of the present invention,according to one embodiment.

FIG. 1A is a detailed view of a distal portion of a spine of anelectrode assembly of FIG. 1.

FIG. 1B is a detailed view of the electrode assembly of FIG. 1 in acollapsed position.

FIG. 2 is a side view of a catheter of the present invention in contactwith atrial issue.

FIG. 3 is a schematic view of the electrode assembly of FIG. 1 deployedin the left atrium.

FIG. 4 is a side cross-sectional view of a proximal junction between adistal end of a catheter body and a proximal end of the electrodeassembly, affording longitudinal movement of the expander, according toone embodiment of the present invention.

FIG. 5 is an end cross-sectional view of the proximal junction of FIG.4, taken along line A-A.

FIG. 6 is a side cross-sectional view of a distal junction betweendistal ends of the expander and the spines of the electrode assembly, inaccordance with one embodiment of the present invention.

FIG. 7 is an end cross-sectional view of the distal junction of FIG. 6,taken along line A-A.

FIG. 8 is an end view of the distal junction of FIG. 6, taken along lineB-B.

FIG. 9 is a perspective view of a puller wire anchor member, inaccordance with one embodiment.

FIG. 10 is a perspective view of an electrode assembly supportstructure, in accordance with one embodiment.

FIG. 10A is a perspective view of a hollow cylindrical body from whichthe electrode assembly support structure of FIG. 10 is formed.

FIG. 11 is a side view of an electrode assembly of the presentinvention, in accordance with another embodiment.

FIG. 11A is a side view of the electrode assembly of FIG. 11, with theexpanded deflected.

FIG. 11B is an end cross-sectional view of the expander of FIG. 11, inaccordance with one embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The invention is directed to a catheter 10 having a basket-shapedelectrode assembly 18 with an expander 22 providing deflectioncapabilities. As shown in FIG. 1, the catheter 10 comprises an elongatedcatheter body 12 having proximal and distal ends and a control handle 16at the proximal end of the catheter body, with the deflectablebasket-shaped electrode assembly 18 being mounted at the distal end ofthe catheter body 12.

The catheter body 12 comprises an elongated tubular construction havinga single, axial or central lumen (not shown), but can optionally havemultiple lumens if desired. The catheter body 12 is flexible, i.e.,bendable, but substantially non-compressible along its length. Thecatheter body 12 can be of any suitable construction and made of anysuitable material. One construction comprises an outer wall made ofpolyurethane or PEBAX.RTM. (polyether block amide). The outer wallcomprises an imbedded braided mesh of stainless steel or the like toincrease torsional stiffness of the catheter body 12 so that, when thecontrol handle 16 is rotated, the distal end of the catheter body willrotate in a corresponding manner.

The outer diameter of the catheter body 12 is not critical, but may beno more than about 8 french, more preferably 7 french. Likewise thethickness of the outer wall is not critical, but is preferably thinenough so that the central lumen can accommodate a puller wire, leadwires, sensor cables and any other wires, cables or tubes. If desired,the inner surface of the outer wall is lined with a stiffening tube (notshown) to provide improved torsional stability. An example of a catheterbody construction suitable for use in connection with the presentinvention is described and depicted in U.S. Pat. No. 6,064,905, theentire disclosure of which is incorporated herein by reference.

The basket-shaped electrode assembly 18 is mounted to the distal end ofthe catheter body 12. As shown in FIG. 2, the basket-shaped electrodeassembly 18 comprises at plurality of spines 20 or arms (e.g., betweenabout five to ten, and preferably about eight) mounted, generallyevenly-spaced in about 360 radial degrees around the expander 22 so thatthe expander forms the center longitudinal axis of the electrodeassembly. The spines 20 are all attached, directly or indirectly, to theexpander 22 at their distal ends, and to the catheter body 12 at theirproximal ends. In accordance with a feature of the present invention, adistal end 22D of the expander 22 is located inside or inwardly of thespines 20 where the distal end 22D of the expander is generallyencircled or surrounded by the spines 20.

With reference to FIG. 1A, each spine has a bowed, electrode-bearingportion 20B and a generally straight distal portion 20D. The distalportion 20D is generally coaxial with the expander 22. The bowed portion20B is adapted to extend at an angle ⊖ from the distal portion 20D,where the angle ⊖ ranges between about 30 degrees (such as when theelectrode assembly 18 is elongated and collapsed with the expander 22extended distally, see FIG. 1B) and 80 degrees (such as when theelectrode assembly 18 is deployed and radially expanded with theexpander drawn proximally, see FIG. 1). As shown in FIGS. 2 and 3, withthe distal end 22D of the expander being in the interior of the assembly18, the assembly 18 provides a generally smooth profile at its distalend without any protrusion that may otherwise project and puncturetissue 13 in the atrium. Moreover, with a generally smooth profile atits distal end, the assembly 18 can be pivoted in a circular motionwhere its longitudinal axis traces a cone C to improve electrode contactwith minimum risk of damage to tissue, especially in a cavernous region,such as an atrium.

As described in more detail below, the expander 22 is movedlongitudinally relative to the catheter body 12 to radially expand orcontract the electrode assembly 18, so that in the radially expandedposition the spines 20 bow outwardly (FIG. 1) and in the elongatedposition the spines less bowed and straighter (FIG. 1B). As will berecognized by one skilled in the art, the number of spines 20 can varyas desired depending on the particular application, so that the assembly18 has at least two spines, preferably at least three spines, and asmany as eight or more spines. As used herein, the term “basket-shaped”in describing the electrode assembly 18 is not limited to the depictedconfiguration, but can include other designs, such as spherical oregg-shaped designs, that include a plurality of expandable armsconnected, directly or indirectly, at their proximal and distal ends.

With reference to FIG. 4, each spine 20 comprises a flexible wire 24with a non-conductive covering 26 on which one or more ring electrodes28 are mounted. In an embodiment, the flexible wires 24 each comprise aflat Nitinol wire, and the non-conductive coverings 26 each comprise abiocompatible plastic tubing, such as polyurethane or polyimide tubing.Alternatively, the spines 20 can be designed without the internalflexible wire 24 if a sufficiently rigid nonconductive material is usedfor the non-conductive covering 26 to permit radial expansion of theelectrode assembly 18, so long as the spine has an outer surface that isnon-conductive over at least a part of its surface for mounting of thering electrodes 28.

Each of the ring electrodes 28 on the spines 20 is electricallyconnected to an appropriate mapping or monitoring system and/or sourceof ablation energy by means of an electrode lead wire 29. Each electrodelead wire 29 extends through the control handle 16, through a lumen inthe catheter body 12, and into the non-conductive covering 26 of thecorresponding spine 20. Each lead wire 29 is attached to itscorresponding ring electrode 28 by any suitable method.

One method for attaching a lead wire 29 to a ring electrode 28 involvesfirst making a small hole through the wall of the non-conductivecovering 26. Such a hole can be created, for example, by inserting aneedle through the non-conductive covering 26 and heating the needlesufficiently to form a permanent hole. The lead wire 29 is then drawnthrough the hole by using a microhook or the like. The end of the leadwire 29 is then stripped of any coating and welded to the underside ofthe ring electrode 28, which is then slid into position over the holeand fixed in place with polyurethane glue or the like. Alternatively,each ring electrode 28 is formed by wrapping a lead wire 29 around thenon-conductive covering 26 a number of times and stripping the lead wireof its own insulated coating on its outwardly facing surfaces.

As shown in FIG. 4, the expander 22 is generally coaxial with thecatheter body 12. The expander 22 has a distal end that is interior ofthe assembly 18 and proximal of the distal end of the electrode assembly18. The expander 22 has a suitable length such that it has a proximalend 22P (FIG. 1) that is exposed proximally of the control handle 16, alonger proximal portion that extends through a central lumen catheterbody 12, and a shorter exposed distal portion extending distally of thecatheter body 12 and through the assembly 18. The expander 22 isafforded longitudinal movement relative to the catheter body so that itcan move the distal ends of the spines 20 proximally or distallyrelative to the catheter body 12 to radially expand and contract,respectively, the electrode assembly. The expander 22 comprises amaterial sufficiently rigid to achieve this function. In an embodiment,the expander 22 comprises braided polyimide tubing 23, i.e., tubinghaving inner and outer layers of polyimide with a braided stainlesssteel mesh therebetween, as is generally known in the art.

With reference to FIGS. 4 and 5, the expander 22 has a center, on-axisguidewire lumen 30 that extends along its entire length. As understoodin the art, the guidewire lumen 30 permits a guidewire to extend throughthe entire length of the catheter for introduction of the catheter 10into a patient's body. Additionally, in accordance with a feature of thepresent invention, the expander 22 also has at least one off-axis lumen31 for uni-directional deflection, or also a second,diametrically-opposite, off-axis lumen 33 for bi-directional deflection,of the assembly 18. Puller wire 35 extends through lumen 33 and pullerwire 37 extends through lumen 31. The proximal ends of the puller wiresare anchored in the control handle 16 to be controlled by a deflectionactuator 17 (FIG. 1). The distal end of each puller wire is anchored ator near the distal end 22D of the expander 22, as described below.Surrounding each puller wire 35 and 37 is a respective compression coil41 and 42. Each compression coil has a proximal end at or near thejunction between the control handle 16 and the catheter body 12, and adistal end at or near the distal end of the catheter body 12.Accordingly, when a selected puller wire on one side of the expander isdrawn proximally by manipulation of the deflection actuator 17, thecompression coil of that puller wire extending through the catheter body12 resists compression along its length so that the puller wire deflectsthe expander 22 distal of the catheter body 12 to that side of theexpander. In accordance with a feature of the present invention,deflecting the expander 22 can change the degree of bowing in the spines20. In the illustrated embodiment of FIG. 2, the degree of bowingincreases (with the spines having greater curvature) on the side of thedeflection and the degree of bowing decreases (with the spines havinglesser curvature) on the side opposite the deflection. For example, theincrease in bowing advantageously enables the spines to exert greaterpressure on the atrial tissue for better contact between the tissue andthe electrodes on the spines. Thus, a user can change the shape of theelectrode assembly by adjusting the longitudinal extension or withdrawalof the expander and/or by adjusting the direction and degree ofdeflection of the expander. In that regard, longitudinal extension orwithdrawal of the expander results in radially symmetrical change oradjustment in the electrode assembly with the degree of curvature ofeach spine being affected similarly, whereas deflection of expanderresults in radially asymmetrical changes with the degree of curvature ofeach spine being affected differently depending on their positionrelative to the deflection of the expander.

An embodiment of a proximal junction between the proximal end of theelectrode assembly 18 and distal end of the catheter body 12 is shown inFIGS. 4 and 5. In FIG. 4, only one spine 20 of the electrode assembly 18is shown for clarity. The junction includes a short plastic housing ortubing 43, which may be made of PEEK (polyetheretherketone). The housing43 joins the distal end of the catheter body 12 and proximal end of theelectrode assembly 18. In one embodiment, the plastic housing 43 has alength of about 11 mm. If the plastic housing 43 is too long, it candisadvantageously affect the flexibility of the distal end of thecatheter body. The proximal end of the plastic housing 43 is mounted onthe distal end of the catheter body 12 by any suitable method, forexample, with polyurethane glue or the like.

The proximal junction also includes an outer proximal ring 48 inside thehousing 43, and a tunnel member 46 in a center through-hole xx of thering 48. Proximal ends of the flexible Nitinol wires 24 are mounted, forexample, evenly-spaced, between the outer proximal ring 48 and thetunnel member 46, both of which may be made of polyimide. The outerproximal ring 48 and the tunnel member 46 may be relatively short, e.g.,about 3 mm in length, compared to the length of the housing 43. Thetunnel member 46 provides the electrode lead wires 29 with longitudinalmovement within the catheter body 12 so that they do not break when thecatheter body 12 bends. To that end, the tunnel member 46 has multipleoff-axis lumens 44 through which the lead electrodes 29 extend and areallowed longitudinal movement. The lumens 44 may be equally spacedradially around the tunnel member 46. The tunnel member 46 also has acenter lumen 49, through which the expander 22 extends and is allowedlongitudinal movement. The outer proximal ring 48, the proximal ends ofthe wires 24 and the tunnel member 46 may be held in place in theproximal junction with polyurethane glue 45 or the like. The proximalends of the non-conductive coverings 26 of the spines 20 also extendinto the plastic housing 43, but proximal ends of the wires 24 arestripped of the coverings 26 so that only the exposed wires 24 aremounted and anchored between the tunnel member 46 and outer proximalring 48.

An embodiment of a distal junction between the distal end of theexpander 22 and the distal ends of the spines 20 is depicted in FIGS. 6,7 and 8. In FIG. 6, only one spine 20 of the assembly 18 is shown forclarity. The distal junction includes an outer tubing 40, which may bemade of polyurethane or polyimide. The distal end 22D of the expanderextends into the outer tubing 40 where it abuts with a proximal face ofa puller wire anchor member 38. In the disclosed embodiment, the member38 has a generally solid cylindrical body 70 with a guidewire lumen 71that is generally axially aligned with the guidewire lumen 30 of theexpander 22. The member 38 also has two diametrically opposed, off-axislumens 71 and 73 that are generally axially aligned with the lumens 31and 33, respectively, of the expander. A U-shaped channel 75 is formedin a distal end of the body 70 which extends between the lumens 71 and73. Accordingly, the puller wires 35 and 37 may be a continuous singletensile member that wraps around the distal end of the member 38 via thechannel 75. This continuous pathway for the puller wire occupies minimalspace in the distal junction and obviates the need to separately anchoreach distal end of two puller wires. It is noted that the guidewirelumen 71 in the member 38 may have a slight bend off the longitudinalaxis to accommodate the U-shaped channel 75, or vice versa where theU-shaped channel 75 may be situated slightly off-center to accommodatethe guidewire lumen 71.

With reference to FIGS. 6, 7 and 8, a ring 62 shorter than the outertubing 40 sits in the tubing 40 and surrounds at least a distal portionof the member 38. The ring 62 may be made of metal or plastic. Thedistal ends of the flexible Nitinol wires 24 that form the spines 20 aremounted, for example, evenly-spaced, between the generally rigid ring 42and the member 38. The outer tubing 40 covers the entire distaljunction. The distal junction, including the outer tubing 40, the ring42, the member 38, as well as the distal ends of the wires 24, is heldtogether by polyurethane glue 63 or the like. The outer tubing 40 longerthan the member 38, so that its proximal end extends over the distal endof the expander 22 and its distal end extends beyond the distal end ofthe member 38. The proximal end of the outer tubing 40 reinforces theattachment between the expander and the member 38. The non-conductivecoverings 26 of the wires 24 extend into the outer tubing 40 but distalends of the flexible wires 24 are stripped of the coverings 26 so thatonly the exposed wires 24 are mounted and anchored between the ring 42and the member 38.

With the proximal and distal junctions anchoring the proximal and distalends of the spines 20, the expander 22 can extend or withdraw each spinerelative to the distal end of the catheter body 12. The proximaljunction affords longitudinal movement of the expander 22 whileanchoring the proximal ends of the spines 20. The distal junctionanchors the distal ends of the spines 20 to the distal end 22D of theexpander so that they are responsive to movement of the expander.Advantageously, the distal junction is proximal of the distal end of theelectrode assembly 18 and interior of the electrode assembly 18 suchthat the electrode assembly has a generally smooth distal surface andprofile so that the distal end of the electrode assembly can contacttissue. Moreover, the rounded distal end of the electrode assemblyallows the assembly to be pivoted or moved in a circular motion (withthe longitudinal axis of the assembly tracing a cone C, as shown in FIG.2) to contact circumferentially-surrounding tissue.

FIGS. 10 and 10A show an electrode assembly support structure 80 that isformed from a hollow cylindrical body 81 that is precision-cut, e.g.,laser cut, and shaped to a structure having a proximal stem portion 80Pand a distal basket portion 80D. A plurality of parallel elongated spinesupports 83 extending along the length of the body 81 are formed bycutting and removing parallel elongated strips 84 that extend from afirst location X in the stem portion 80P to the distal end of thecylindrical body 81. A significant distal portion of each spine supportis bowed, or otherwise bent outwardly with a curvature, at a secondlocation Y distal of the first location X to form the basket-shape ofthe assembly 18. A straight distal end portion 83D of each spine supportis bent inwardly toward the proximal stem portion 80P for attachment tothe distal end of the expander by a distal junction. The proximal stemmay be inserted into the distal end of the catheter body up to thesecond location Y and attached thereto by a proximal junction to allowfor longitudinal movement of the expander 22. To that end, the stemportion 80P may be mounted between the proximal outer ring 48 and thetunnel member 46. The structure 80 is constructed of any suitably rigidmaterial with shape material, e.g., Nitinol, so as to allow thestructure to be flexible, elastic and sufficiently rigid to hold apredetermined configuration, yet be deformable under an applied forceand able to resume the predetermined configuration upon removal of theapplied force.

The catheter further includes two location sensors 32 and 34 forproviding location information about each of the ring electrodes 28 onthe electrode assembly 18. A proximal location sensor 34 is mountedwithin the proximal junction, in the housing 43. And the distal locationsensor 32 is mounted in the distal junction, in the outer tubing 40.

Each location sensor 32 and 34 is connected to a corresponding sensorcable 36 that extends through the catheter body 12 and control handle 16and out the proximal end of the control handle within an umbilical cord(not shown) to a sensor control module (not shown) that houses a circuitboard (not shown). Alternatively, the circuit board can be housed withinthe control handle 16, for example, as described in U.S. Pat. No.6,024,739, the disclosure of which is incorporated herein by reference.The sensor cable 36 comprises multiple wires encased within a plasticcovered sheath. In the sensor control module, the wires of the sensorcable are connected to the circuit board. The circuit board amplifiesthe signal received from the corresponding location sensor and transmitsit to a computer in a form understandable by the computer by means ofthe sensor connector at the proximal end of the sensor control module.Also, because the catheter is designed for single use only, the circuitboard may contain an EPROM chip that shuts down the circuit boardapproximately twenty-four hours after the catheter has been used. Thisprevents the catheter, or at least the location sensor, from being usedtwice.

In one embodiment, each location sensor 32 and 34 comprises amagnetic-field-responsive coil, as described in U.S. Pat. No. 5,391,199,or a plurality of such coils, as described in International PublicationWO 96/05768. The plurality of coils enables six-dimensional position andorientation coordinates to be determined. Alternatively, any suitableposition sensor known in the art may be used, such as electrical,magnetic or acoustic sensors. Suitable location sensors for use with thepresent invention are also described, for example, in U.S. Pat. Nos.5,558,091, 5,443,489, 5,480,422, 5,546,951, and 5,568,809, andInternational Publication Nos. WO 95/02995, WO 97/24983, and WO98/29033, the disclosures of which are incorporated herein by reference.In one embodiment, an electromagnetic mapping sensor has a length offrom about 3 mm to about 7 mm, preferably about 4 mm.

Alternatively, one of the location sensors 32 and 34 can comprise a bendsensor, which generates signals responsive to a bend radius of thespines 20. Such a bend sensor can comprise one or more piezoelectricsensors, as are known in the art, which generate electrical signalsproportional to a force or torque exerted thereon when the catheterbends. Alternatively, a bend sensor can comprise one or more strainsensors, as are known in the art, or a fiber optic sensor, wherein thebend radius is determined by measuring the loss and/or back-reflectionof light in an optical fiber, as is also known in the art.

The coordinates of the distal sensor 32, relative to those of theproximal sensor 34, are determined and taken together with other knowninformation pertaining to the curvature of the spines 20 of thebasket-shaped mapping assembly 18. This information is used to find thepositions of the ring electrodes 28 mounted on the spines 20.

In the depicted embodiment of FIG. 4, the proximal location sensor issituated in a second tunnel 50 provided at the proximal junction.Proximal end of the second tunnel extends into the catheter body 12 anddistal end of the second tunnel extends into the housing 43. The tunnel50 may be made of polyimide and has a length ranging from about 5 to 7mm. The tunnel 50 protects the expander 22, electrode lead wires 29 andthe sensor cable 36 that is attached to the distal location sensor 32from being glued to the catheter at the junction of the catheter body 12and housing 43 during assembly. Prior to assembly, the proximal locationsensor 34 is mounted in a window 52 of the second tunnel 50. Theproximal location sensor may have a length of about 1 to 3 mm. Thesensor cable 36 attached to the proximal location sensor 34 extendsthrough the second tunnel 50 and catheter body 12 along with the othercomponents. Accordingly, the cable 36 for the proximal sensor isafforded longitudinal movement at the proximal junction.

The distal location sensor 32 is mounted at or near the distal end ofthe electrode assembly 18. In the depicted embodiment of FIG. 6, thedistal location sensor is mounted between the outer tubing 44 and themember 38 and held in place by the glue 63. The sensor cable 36 attachedto the distal location sensor 32 extends through one of thenon-conductive coverings 26 and into the distal end of the catheter body12.

As would be recognized by one skilled in the art, other arrangements forconstructing the proximal and distal junctions and for mounting thelocation sensors could also be used in accordance with the invention.

Deflection of the expander 22 relative to the catheter body 12, whichresults in deflection of the electrode assembly 18, is accomplished bymanipulation of the control handle 16. As shown in FIG. 1, the controlhandle 16 comprises a generally cylindrical housing in which mechanismsare provided for actuating uni- or bi-directional deflection of theexpander. In the illustrated embodiment, the control handle has adeflection arm 18 adapted for the user to manipulate the puller wires 35and 37 for deflecting the expander bi-directional. Rotation of thedeflection arm 18 to one direction deflects the expander in thatdirection. Rotation of the deflection arm 18 to the opposite directiondeflects expander in the opposite direction. A suitable control handleis described in U.S. Pat. No. 7,377,906, entitled STEERING MECHANISM FORBI-DIRECTIONAL CATHETER and U.S. Pat. No. 8,137,308, entitled CATHETERWITH ADJUSTABLE DEFLECTION SENSITIVITY, the entire disclosures of whichare hereby incorporated by reference.

In an alternate embodiment as shown in FIG. 11, electrode assembly 118comprises a plurality of spines 120 or arms (e.g., between about threeto five, and preferably about four) mounted, for example, generallyevenly-spaced, in about 180 radial degrees around expander 122.

The spines 120 are all attached, directly or indirectly, to the expander122 at their distal ends, and to the catheter body 112 at their proximaland distal ends, as described above. In the illustrated embodiment ofFIG. 11A, the degree of bowing increases (with the spines having greatercurvature) on the side of the deflection and the degree of bowingdecreases (with the spines having lesser curvature) on the side oppositethe deflection. Thus, a user can change the shape of the electrodeassembly by adjusting the longitudinal extension or withdrawal of theexpander and/or by adjusting the direction and degree of deflection ofthe expander 122.

The expander 122 of assembly 118 may also carry a plurality of ringelectrodes 128 in addition to those carried on the spines. As shown inFIG. 11B, tubing 123 of the expander 122 includes a fourth lumen 85through which lead wires 129 extend. As such, the expander spine 122 isadapted for tissue contact in addition to providing support anddeflection to the basket assembly 118.

To use the catheter of the invention, an electrophysiologist introducesa guiding sheath, guidewire and dilator into the patient, as isgenerally known in the art. A suitable guiding sheath for use inconnection with the inventive catheter is the PREFACE™ Braided GuidingSheath (commercially available from Biosense Webster, Inc., Diamond Bar,Calif.). The guidewire is inserted, the dilator is removed, and thecatheter is introduced through the guiding sheath whereby the guidewirelumen in the expander permits the catheter to pass over the guidewire.As shown in FIG. 3, the catheter is first introduced to the right atriumRA via the inferior vena cava IVC , where it passes through the septum Sin order to reach the left atrium LA.

The guiding sheath covers the spines of the electrode assembly in acollapsed position so that the entire catheter can be passed through thepatient's vasculature to the desired location. The expander may bepositioned distally of the catheter body to allow the spines of theassembly to be flattened while the assembly is passed through theguiding sheath. Once the distal end of the catheter reaches the desiredlocation, e.g., the left atrium, the guiding sheath is withdrawn toexpose the electrode assembly. The expander is drawn proximally orotherwise manipulated so that the spine flex outwardly between thedistal and proximal junctions. With the electrode assembly radiallyexpanded, the ring electrodes contact atrial tissue. As recognized byone skilled in the art, the electrode assembly can be fully or partiallyexpanded, straight or deflected, in a variety of configurationsdepending on the configuration of the region of the heart being mapped.

Using the ring electrodes on the spines (and/or the expander) incombination with the distal end proximal location sensors 32 and 34, theelectrophysiologist can map local activation time and/or ablate, whichcan guide the electrophysiologist in diagnosing and providing therapy tothe patient. The catheter can include one or more reference ringelectrodes mounted on the catheter body, or one or more referenceelectrodes can be placed outside the body of the patient. By using theinventive catheter with the multiple electrodes on the basket-shapedelectrode assembly, the electrophysiologist can obtain a true anatomy ofa cavernous region of the heart, including an atrium, by measuring lesspoints than with traditional catheters, allowing him to map the regionmore quickly. Moreover, the electrophysiologist can pivot the electrodeassembly about its distal end such that the longitudinal axis of theassembly sweeps out a cone to readily bring more radial ring electrodesinto contact with surrounding tissue for mapping and/or ablation withoutfear of puncturing tissue. Furthermore, by deflecting the expander,selected ring electrodes can be easily brought into contact with atrialtissue for improved sensing and ablation.

The preceding description has been presented with reference to presentlydisclosed embodiments of the invention. Workers skilled in the art andtechnology to which this invention pertains will appreciate thatalterations and changes in the described structure may be practicedwithout meaningfully departing from the principal, spirit and scope ofthis invention. As understood by one of ordinary skill in the art, thedrawings are not necessarily to scale. Accordingly, the foregoingdescription should not be read as pertaining only to the precisestructures described and illustrated in the accompanying drawings, butrather should be read consistent with and as support to the followingclaims which are to have their fullest and fair scope.

What is claimed is:
 1. A catheter comprising: an elongated catheter body having proximal and distal ends and at least one lumen therethrough; an electrode assembly at the distal end of the catheter body, the electrode assembly having proximal and distal ends and comprising a plurality of spines, the spines comprising a plurality of electrodes; an expander having proximal and distal ends, the expander forming a longitudinal axis of the assembly, the spines attached at their proximal and distal ends to the expander; at least one puller wire that extends through the expander, the puller wire having a distal end anchored in the expander at a location distal of the distal end of the catheter body and proximal of the distal end of the assembly; and a control handle proximal of the catheter body, the control handle having an actuator adapted to move the at least one puller wire, wherein the electrode assembly has an expanded arrangement when the expander is moved proximally along the longitudinal axis relative to the catheter body and the electrode assembly has a collapsed arrangement when the expander is moved distally along the longitudinal axis relative to the catheter body, and wherein the expander is adapted to deflect in at least one direction when the at least one puller wire is moved by the actuator.
 2. The catheter of claim 1, further comprising a proximal junction at the distal end of the catheter body, the proximal junction comprising: a tubing having a proximal end and a distal end, the proximal end being mounted over the distal end of the catheter body; a ring inside the distal end of the tubing, the ring having a through-hole; and a tunnel member 46 in the through-hole of the ring, wherein the tunnel member has a lumen through which the expander extends and has longitudinal movement.
 3. The catheter of claim 2, wherein the tunnel member has at least one off-axis lumen.
 4. The catheter of claim 1, further comprising a distal junction at the distal end of the expander, the distal junction comprising: an outer tubing having a lumen; a puller wire anchor in the lumen of the outer tubing; and a ring in the lumen of the outer tubing, wherein distal ends of spine support members are anchored between the ring and the puller wire anchor.
 5. The catheter of claim 1, wherein the spines are mounted in about 360 radial degrees around the expander.
 6. The catheter of claim 1, wherein the spines are mounted in about 180 radial degrees around the expander.
 7. The catheter of claim 1, wherein at least one spine carries at least one ring electrode.
 8. The catheter of claim 1, wherein the expander carries at least one ring electrode distal of the distal end of the catheter body.
 9. The catheter of claim 1, wherein the expander has a guidewire lumen.
 10. The catheter of claim 1, further comprising at least one location sensor.
 11. A catheter comprising: an elongated catheter body having proximal and distal ends and at least one lumen therethrough, the catheter body defining a longitudinal axis; an electrode assembly at the distal end of the catheter body, the electrode assembly having proximal and distal ends and comprising a plurality of spines, the spines comprising a plurality of electrodes; an expander having proximal and distal ends, the expander forming a longitudinal axis of the assembly, the spines attached at their proximal and distal ends to the expander; at least one puller wire that extends through the expander, the puller wire having a distal end anchored in the expander at a location distal of the distal end of the catheter body and proximal of the distal end of the assembly; and a control handle proximal of the catheter body, the control handle having an actuator adapted to move the at least one puller wire, wherein the expander is adapted for longitudinal movement relative to the catheter body and for deflection relative to the longitudinal axis.
 12. The catheter of claim 11, wherein the electrode assembly is adapted to assume an expanded configuration in response to longitudinal movement of the expander relative to the catheter body.
 13. The catheter of claim 11, wherein the electrode assembly is adapted to assume an asymmetrical configuration in response to deflection of the expander relative to the longitudinal axis.
 14. The catheter of claim 11, wherein each spine is adapted to assume a bowed configuration with a degree of curvature.
 15. The catheter of claim 14, wherein the degree of curvature of each spine changes similarly in response to longitudinal movement of the expander relative to the catheter body.
 16. The catheter of claim 14, wherein the degree of curvature of each spine changes differently in response to deflection of the expander relative to the catheter body.
 17. The catheter of claim 11, further comprising a distal junction between a distal end of the expander and distal ends of the spines, wherein the distal junction is proximal of a distal end of the electrode assembly.
 18. The catheter of claim 11, wherein the spines are mounted in about 360 radial degrees around the expander.
 19. The catheter of claim 1, wherein the spines are mounted in about 180 radial degrees around the expander.
 20. The catheter of claim 1, wherein at least one spine carries at least one ring electrode. 